The National Center for Environmental Assessment (NCEA) in the EPA's Office of Research and Development (ORD) develops toxicological reviews/assessments for various chemicals for inclusion in the IRIS database. NCEA is developing a draft Toxicological Review of tert-Butyl Alcohol (tert-butanol) and Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) and has asked the SAB to conduct the peer review of these draft documents.

These two draft EPA documents represent new IRIS assessments of tert-butanol and ETBE. Experimental animal data and other relevant data from studies of the noncancer and cancer effects of tert-butanol and ETBE are evaluated in these assessments. These assessments include an oral reference dose (RfD) and inhalation reference concentration (RfC) for noncancer effects as well as a cancer assessment. The cancer assessments characterize tert-butanol and ETBE as having suggestive evidence of carcinogenic potential to humans and include oral cancer slope factors for both compounds and an inhalation unit risk for ETBE.